...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Hydrogen is a preferred intermediate in the energy-conserving electron transport chain of Methanosarcina barken
【24h】

Hydrogen is a preferred intermediate in the energy-conserving electron transport chain of Methanosarcina barken

机译：氢是甲烷八叠球菌的节能电子传输链中的优选中间体

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Methanogens use an unusual energy-conserving electron transport chain that involves reduction of a limited number of electron acceptors to methane gas. Previous biochemical studies suggested that the proton-pumping F_(420)H_2 dehydrogenase (Fpo) plays a crucial role in this process during growth on methanol. However, Methanosarcina barkeri △fpo mutants constructed in this study display no measurable phenotype on this substrate, indicating that Fpo plays a minor role, if any. In contrast, △frh mutants lacking the cytoplasmic F_(420)-reducing hydrogenase (Frh) are severely affected in their ability to grow and make methane from methanol, and double △fpo/△frh mutants are completely unable to use this substrate. These data suggest that the preferred electron transport chain involves production of hydrogen gas in the cytoplasm, which then diffuses out of the cell, where it is reoxidized with transfer of electrons into the energy-conserving electron transport chain. This hydrogen-cycling metabolism leads directly to production of a proton motive force that can be used by the cell for ATP synthesis. Nevertheless, M. barkeri does have the flexibility to use the Fpo-dependent electron transport chain when needed, as shown by the poor growth of the △frh mutant. Our data suggest that the rapid enzymatic turnover of hydrogenases may allow a competitive advantage via faster growth rates in this freshwater organism. The mutant analysis also confirms the proposed role of Frh in growth on hydrogen/carbon dioxide and suggests that either Frh or Fpo is needed for aceticlastic growth of M. barkeri.
机译：产甲烷菌使用不寻常的节能电子传输链，该链涉及将有限数量的电子受体还原为甲烷气体。先前的生化研究表明，质子泵浦的F_（420）H_2脱氢酶（Fpo）在此过程中在甲醇上生长过程中起着至关重要的作用。但是，在这项研究中构建的巴氏甲烷八叠球菌Δfpo突变体在该底物上没有可测量的表型，表明Fpo的作用很小（如果有）。相比之下，缺乏胞质F_（420）还原氢酶（Frh）的△frh突变体的生长能力和从甲醇制取甲烷的能力受到严重影响，而双重△fpo /△frh突变体完全不能使用该底物。这些数据表明，优选的电子传输链涉及在细胞质中产生氢气，然后氢气扩散出细胞，并在其中通过电子转移进入能量节约的电子传输链而被再氧化。这种氢循环代谢直接导致质子原动力的产生，质子原动力可被细胞用于ATP合成。然而，正如△frh突变体的不良生长所表明的那样，巴克氏杆菌确实具有在需要时使用Fpo依赖性电子传输链的灵活性。我们的数据表明，在这种淡水生物中，酶的快速酶促转化可能通过更快的生长速度而带来竞争优势。突变分析还证实了Frh在氢/二氧化碳生长中的拟议作用，并暗示Frh或Fpo是巴克利氏菌的破弹孔生长所必需的。

著录项

  • 来源
  • 作者

    Gargi Kulkarni; Donna M. Kridelbaugh; Adam M. Guss; William W. Metcalf;

  • 作者单位

    Department of Microbiology, University of Illinois at Urbana-Champaign, B103 Chemical and Life Science Laboratory, Urbana, IL 61801-3763;

    Department of Microbiology, University of Illinois at Urbana-Champaign, B103 Chemical and Life Science Laboratory, Urbana, IL 61801-3763 Department of Biology, Western Kentucky University, Bowling Green, KY 42101;

    Department of Microbiology, University of Illinois at Urbana-Champaign, B103 Chemical and Life Science Laboratory, Urbana, IL 61801-3763 Thayer School of Engineering, Hanover, NH 03755;

    Department of Microbiology, University of Illinois at Urbana-Champaign, B103 Chemical and Life Science Laboratory, Urbana, IL 61801-3763;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    hydrogen electron transport; F_(420); H_2 cycling; methanogenesis;

    机译：氢电子传输F_（420）;H_2循环;产甲烷;

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号